Method and moil configuration for trimming non-circular containers

ABSTRACT

The invention includes a method and moil configuration to trim non-circular products. The moil may include a cam having surfaces that employ principles of the Reuleaux triangle, i.e., the cam surfaces represent surfaces of constant width.

BACKGROUND OF THE INVENTION

[0001] The present invention generally relates to apparatus and methods for trimming moils molded products. More specifically, the invention relates to moil configurations.

[0002] In 1853, railroad magnate Commodore Cornelius Vanderbilt, dining at a Saratoga Springs, N.Y., resort, sent his fried potatoes back to the chef, complaining that they were too thick. The chef that evening was Native-American George Crum, who was apparently miffed at Vanderbilt's complaint and decided it deserved a sarcastic reply. He sliced potatoes paper thin, fried them to a crisp in boiling oil, and salted them. The Commodore loved the “crunch potato slices,” as he called them, and the “Saratoga Chips” became a restaurant fad from that day forward.

[0003] Since their invention, potato chips have been distributed to consumers in a variety of containers, from kettle drums to bags. To account for the irregular shape of the chips, container designers conventionally developed the chip container around the collective size volume of the chips so that the container held the desired volume by weight of chips. However, the irregular shape of potato chips resulted in containers having large size volumes, which, in turn increased the cost of the product due to additional shipping and shelving space costs.

[0004] In more modem times, potato chips have been designed with a circular, flat shape so as to efficiently fit within a cylindrical canister (sometimes referred to as a can). For a given volume by weight of chips, the size volume of the chip container was dramatically reduced. This development in potato chip technology was widely accepted by the buying public and manufacturers alike. If a noncircular chip or other product were developed, it may be useful for the shape of the chip canister to follow the shape of the non-circular product.

[0005] Products, such as containers, may be manufactured through the inexpensive process of blow molding plastic into the desired shape. In the formation of blow molded plastic products, the top of the product may include an outwardly extending flange to serve as a lip to aid in sealing the container with a removable lid. Additionally, a manufacturing handling appendage may be formed on the top lip of the initial product. This manufacturing handling appendage, called a moil, eventually is removed from the initial product to reveal the top lip.

[0006] The moil may be removed by rolling or fixedly rotating the product about its longitudinal axis between two rails where one of the rails includes a stationary knife edge aligned at the moil/container opening trim line. After the moil is removed by this spin trimming process, the container opening is exposed and the container is ready to receive the potato chips and the removable lid.

[0007] In the case of a container having a circular cross section at the trim line, the angular relationship between a stationary metal knife blade and the surface being cut may be held relatively constant at each trim point during the spin trimming process. An ideal angular relationship may be where the blade edge is held perpendicular to the thickness of the container wall at each cut point. This cut of alignment minimizes the length over which the blade is used for a given trim segment.

SUMMARY OF THE INVENTION

[0008] The invention includes a non-circular product having a container and a moil and provides a method to separate the container from the moil at a trim line. The container may have a cross section that defines at least one flat side. For example, the cross section may be a polygon in the shape of a triangle. The polygon cross section may also define a plurality of vertices that define a smooth curve. In one aspect of the invention, the container includes a lip disposed between the trim line and the container.

[0009] The moil, which may be thought of as a manufacturing handling appendage, is connected to the container at the trim line. A cam may be formed as part of the moil such that the non-circular product follows the cam profile as the non-circular product rotates. This cam may have at least one lobe. In one aspect of the invention, the cam assumes the shape of a closed curve of constant width such as that which defines an equilateral configuration. One closed curve of constant width that may be used includes a plurality of segments that are derived from the principles of the Reuleaux triangle.

[0010] The cam may be a first cam where the moil includes a second cam such that the first cam is disposed between the container and the second cam. This arrangement may form a groove. In another aspect of the invention, the first cam and the lip form a trim groove having a first opening distance. Here, the first cam may be part of a guide where the guide further includes one depression formed into the guide at an angle that presents a second opening distance. This second opening distance may be greater than the first opening distance. In a further embodiment, the first cam defines a plurality of non-circular curves of constant width and a lever is disposed above the first cam. In operation, the non-circular product may be placed in a trimming machine. The trimming machine having a blade, a first rail, and a second rail, where the trim line aligns with the blade and the first cam is disposed between the first rail and the second rail. The non-circular product may be urged over the blade. In one aspect of the invention, the first cam is engaged with a conveyor belt. In another aspect, the non-circular product is moved along a bottom guide.

[0011] These and other features of the invention are discussed in greater detail below in the following detailed description of the presently preferred embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 illustrates a side view of a product embodying principles of the invention;

[0013]FIG. 2 is an isometric view of the product of FIG. 1;

[0014]FIG. 3 is a detailed partial view of the product of FIG. 1;

[0015]FIG. 4A illustrates a Reuleaux triangle;

[0016]FIG. 4A illustrates a construction of a modified Reuleaux triangle in accordance with principles of the invention;

[0017]FIG. 5A illustrates a Reuleaux triangle disposed within a square;

[0018]FIG. 5B illustrates travel of a Reuleaux triangle with a longitudinal channel;

[0019]FIG. 6 is a top view of the product of FIG. 1;

[0020]FIG. 7A is a top view of a trimming machine to trim the product of FIG. 1;

[0021]FIG. 7B is a side view of the trimming machine of FIG. 7A; and

[0022]FIG. 8 illustrates a spin trimming method of the invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0023] In regards to removing a moil from a container having a sealing lip surface by cutting consecutive trim segments, the inventors have determined that minimizing the length over which a blade is used for a given trim segment works to make it more difficult for the blade to bend. By maintaining a rigid blade at a given trim segment, the cut over the newly exposed surface of the lip will be smooth for each trim segment. With a smooth cut, the need to clean the sealing lip surface of the container through facing the lip surface is avoided.

[0024] As the length over which the blade is used for a given trim segment increases, the blade becomes more likely to flex so as to result in uneven cuts over a given trim segment. For uneven cuts, an additional facing process would be needed to clean the sealing lip surface finish of each container, resulting in additional manufacturing costs.

[0025] In the case of a container having a non-circular cross section at the trim line, the angular relationship between the stationary knife and the surface being cut cannot be held relatively constant at each trim point during a conventional spin trimming process as in the case of circular cross section containers. In other words, the length over which the blade is used for a given trim segment for non-circular cross section containers may be at a minimum at some locations and greater than minimum at other locations using the same techniques used for circular cross section containers. For example, the length over which the blade is used for a given trim segment may be at a minimum at the comers of a triangular container and increase as the blade approaches the midpoint of each of the three flat sides. At the side midpoint, the knife blade may act as a chopping guillotine rather than a cutting blade. Chopping the moil from a triangular container or any polygon container would undesirably result in uneven cuts that require facing.

[0026] Smoothly cutting a moil from a polygon container by rolling that product between two rails of a piece of machinery requires that the angular relationship between a stationary knife and the surface being cut be varied. A surprising solution to this problem is to modify the moil to include the curvilinear triangle known as the Reuleaux triangle. As a shape of constant width, a Reuleaux triangle may be rolled between the two parallel rails of a piece of machinery. Moreover, since the centroid of a Reuleaux triangle varies as the Reuleaux triangle rolls forward, the angular relationship between a stationary knife and the surface being cut will varied. Additionally, this solution is inexpensive since a blow molded moil need only be redesigned to include a cam based on a Reuleaux triangle.

[0027]FIG. 1 illustrates a side view of product 100. FIG. 2 is an isometric view of product 100. Product 100 may be any item formed of material that may be cut or trimmed. Such materials may include plastic, glass, metal, wood, and rubber. In one embodiment, product 100 is an item that is the result of a process that includes blow molding melted plastic into a cavity.

[0028] Included with product 100 may be container 102 and moil 104. The collective of the locations at which container 102 and moil 104 meet may define trim line 103. Trim line 103 may be thought of as the points at which container 102 and moil 104 may be separated by, for example, the cutting blade of a knife.

[0029] Container 102 may be any receptacle, such as a carton, can, or jar, in which material may be held or carried. Included with container 102 may be base 106, walls 108, and lip 110. Planes that bisect each of base 106, walls 108, and lip 110 may intersect to define longitudinal axis 112 such that product 100 maybe conceived to rotate uniformly about longitudinal axis 112. Base 106 may serve to support container 102 on a surface so that longitudinal axis 112 remains perpendicular to that surface, irrespective of the contents of container 102.

[0030] Walls 108 may extend from base 106 to lip 110 so as to form cavity 114 (FIG. 3). Any item may be placed within cavity 114 for storage or transportation. To best store and ship flat chips having a triangle shape, a cross section through longitudinal axis 112 of container 102 may define a triangle perimeter as best seen in FIG. 2. Rounded corners may aid in a moil/container trimming process. Accordingly, where container 102 is the result of a blow molding process, rounded comers 115 may be placed at the three intersections of walls 108.

[0031] Lip 110 may be a projecting edge whose perimeter defines an opening in container 102 to cavity 114. The perimeter of lip 110 may circumscribe the perimeter of walls 108, coincide with the perimeter of walls 108, or be circumscribed by the perimeter of walls 108. The features of lip 110 may be adapted to receive a lid, such as a translucent plastic lid generally seen on conventional round potato chip containers.

[0032] As noted above, trim line 103 may separate container 102 and moil 104. Moil 104 may be thought of as an appendage that aids in handling product 100 during the manufacturing process. The structural configuration of moil 104 may be dictated by the features of the particular process machines that make and handle product 100.

[0033] Included with moil 104 may be lever 116, cap 118, and guide 120. Lever 116 may be a projecting handle having features adapted to make physical, manipulating contact with product 100. These features may include a hexagonal hole disposed through a first side of lever 116 at an orientation that is perpendicular to longitudinal axis 112. A second side of lever 116 may include a thickened portion to serve as a stop for a hexagonal carrying rod inserted into the hexagonal hole. Another feature may be an area along a center line of lever 116 that serves as a mating area for the mold sprue.

[0034] Cap 118 may be a curved surface that radially transitions from lever 116 to locations on product 100 that are furthest away from longitudinal axis 1 12. This may aid in distributing melted plastic within a blow mold used to form product 100. In one embodiment, cap 118 may include cam 122 at a location that is remote from longitudinal axis 112. Cam 122 may include a perimeter similar to that of guide 120. Where this is the case, cam 122 and guide 120 may define groove 124. Both groove 124 and cam 122 may aid guide 120 in regulating the movement of product 100 about longitudinal axis 112 (roll) and the movement of product 100 about an axis normal to both longitudinal axis 112 and a movement direction of product 100 (yaw).

[0035]FIG. 3 is a detailed partial view of product 100. As noted above, partial 100 may include guide 120. Guide 120 may be any device that acts to influence or regulate the motion of container 102. As seen in FIG. 3, a continuous interface between guide 120 and lip 110 may form trim groove 126. Trim groove 126 may form a track that aids in retaining a knife blade on trim line 103.

[0036] As a knife blade approaches the midpoints of walls 108 that are flat, the knife blade distance from trim line 103 may increase. This may make it more likely that the leading edge of the knife blade will jump the track formed by trim groove 126. To account for this, guide 120 may include surfaces 128. Surfaces 128 may be depressions formed into guide 120 at an angle that presents a greater opening distance to trim groove 126. This greater opening distance of trim groove 126 may work to make it less likely that the knife blade will jump the trim groove 126 track.

[0037] In addition to surfaces 128, guide 120 may also include cam 130 having cam face 132 residing on its periphery. Cam 130 may be any eccentric or multiply curved wheel that employs cam face 132 to produce relative motion between trim line 103 and a cutting edge. The relative motion may be at least one of variable, reciprocating, alternate, and intermittent motion. Moreover, cam 130 may assume the shape of any closed curve of constant width having more than one curve. When such a closed curve defines an equilateral configuration, that curve may have at least three arcs. Face 132 of cam 130 may be shaped so as to follow projecting parts in its path. Face 132 may include a groove (not shown) that aids in creating the relative motion between trim line 103 and a cutting edge. Additionally, cam 130 maybe positioned on moil 104 so that the centroid of moil 104 coincides with longitudinal axis 112.

[0038] Industrial machinery may move an object forward by rolling that object between two parallel rails as guided by a circular curved surface. For example, an aluminum can may be rolled forward by pacing the can between a stationary lower rail and a moving upper rail. The circular curved surface helps roll the can forward because the width of its circular perimeter is constant when measured anywhere across its perimeter. For a circle, the width and the diameter coincide and may be thought of as an ellipse of which the two axes are equal in length.

[0039] As noted above, the invention may employ principles of the curvilinear triangle known as the Reuleaux triangle so as to take advantage of the constant width and centroid variable movement of the Reuleaux triangle. FIG. 4A illustrates Reuleaux triangle 400. In one embodiment, cam 130 is based on Reuleaux triangle 400. The Reuleaux triangle is a paradox in that, for a given perimeter measurement, a Reuleaux triangle defining a width will have less cross-sectional area than a circle of the same width. In general, a non-circular enclosed curve of constant width has less cross-sectional area than a circle of the same width, but the same perimeter. The Reuleaux triangle is the non-circular curve of least cross-sectional area and works well to hog out the straight edges of a square hole near the comers of the hole (see for example, U.S. Pat. No. 4,074,778, entitled Square Hole Drill).

[0040] The following discussion on the aspects of the Reuleaux triangle is provided to aid in understanding the Reuleaux triangle. To better understand the width of a circle or any shape enclosing an area, pick two parallel lines so that the shape, here a circle, lies between the two lines. Move each line towards the shape all the while keeping each line parallel to its original orientation. After both lines touch the shape, the distance between the two lines is the width of the shape in the direction of the two lines. A shape is of constant width if its width does not depend on the direction from which the lines approach the shape. Any shape having a constant width may be rolled between the two parallel rails of a piece of machinery.

[0041]FIG. 4A illustrates a construction of Reuleaux triangle 400. FIG. 4B illustrates some variations on a construction of a Reuleaux triangle 400, including expanding Reuleaux triangle 400 to the size of Reuleaux triangle 410 having rounded vertices 412. Reuleaux triangle 400 may be developed as follows. Present equilateral triangle 402. Draw three arcs 404, 406, and 408, each centered at one of the vertices of equilateral triangle 402 so that radius of each arc 404, 406, and 408 is equal to the length of a side of equilateral triangle 402. Removing triangle 402 reveals Reuleaux triangle 400.

[0042]FIG. 5A illustrates Reuleaux triangle 400 disposed within square 502. Reuleaux triangle 400 may define Reuleaux centroid 504 whereas square 502 may define center 506. Rotating Reuleaux triangle 400 about center 506 causes the perimeter of Reuleaux triangle 400 to move along the interior sides of square 502. Reuleaux triangle 400 eventually will pass over approximately 91% the interior area of square 502, leaving uncovered only four areas 510 totaling about 8%.

[0043] Centroid 504 does not stay fixed as Reuleaux triangle 400 is rotated about center 506, but moves along path 508. Rather than route a circular course, path 508 routes a variable curve composed of four arcs of an ellipse. Moreover, like any noncircular curve of constant width, Reuleaux triangle 400 always makes contact with each interior side of the parallel sides of square 502 during the entire rotation time.

[0044]FIG. 5B illustrates machinery 512. Machinery 512 may include rail 514 and rail 516. In one embodiment, rails 514 and 516 may be parallel to one another. Each interior side of the parallel sides of square 502 maybe thought of as rails 512 and 514 of machinery 516. In this embodiment, rails 512 and 514 essentially may be viewed as two pairs of parallel lines, equally spaced. Since Reuleaux triangle 400 always makes contact with each interior side of the parallel sides of square 502, Reuleaux triangle 400 may be rolled between rails 512 and 514 where one rail is held stationary relative to the other rail. However, since Reuleaux triangle 400 does not have a constant radius, the velocity of Reuleaux triangle 400 in direction 518 will vary where the rotational velocity of Reuleaux triangle 400 is held constant.

[0045] As seen in FIG. 5B, Reuleaux centroid 504 moves in direction 518 along the variable curve composed of four arcs of an ellipse identified as path 508. In an alternate embodiment, one of rail 514 and 516 may have a surface that is not parallel to the surface of the other rail. For example, rail 514 may transition from flat, parallel surface 520 to one that is composed of arcs 522. Four of arcs 522 may be the above noted four arcs of an ellipse. Over the now variable surface of rail 514, centroid 504 may trace a level line for path 508 as rail 514 rises and falls.

[0046]FIG. 6 is a top view of product 100. In this embodiment, cam 122 includes a top view profile that is identical to cam 130 of FIG. 3. Accordingly, the cam shown in FIG. 4 may be identified as cam 130 for this discussion. Dashed lines are provided in FIG. 4 to illustrate the periphery relationship between cam 130, comers 116, and trim line 103. In this view, trim line 103 may coincide with walls 108.

[0047] Cam 130 may employ Reuleaux triangle 400 with rounded vertices so as to include lobes 602, 604, 606, 608, 610, and 612. If product 100 were rolled in the direction of arrow 614 on surface 616, centroid 618 would rise and fall relative to surface 616 as a function of the lobe that is in contact with surface 616. At the perimeter midpoint of lobe 602, 604, or 606, distance 620 between surface 616 and trim line 103 would be at a maximum in the shown embodiment. At the perimeter midpoint of lobe 608, 610, or 612, distance 620 between surface 616 and trim line 103 would be at a minimum in the shown embodiment. Between these two extremes, distance 620 may vary according the principles of Reuleaux triangle 400.

[0048]FIG. 7A is a top view of trimming machine 700. FIG. 7B is a side view of trimming machine 700. Included with trimming machine 700 may be blade 702, blade rail 704, conveyor system 706 having conveyor belt 708 disposed about wheel 710 and wheel 712, conveyor rail 714, and bottom guide 716. Bottom guide 716 may move product 100 in the direction of arrow 722 as discussed below.

[0049] Blade 702 may be any cutting part of a sharpened tool. For example, blade 702 may be one of a sharp flat-edge of a knife, a wire, a high pressure water jet stream, a rope, and a laser. In the embodiment shown in FIG. 7A, blade 702 is a sharp flat-edge disposed within blade rail 704. Blade 702 may be disposed at an angle to blade rail 704. This may permit a smooth transition when trim line 103 first encounters blade 702 as well as account for the decrease in support structure between moil 104 and container 102 as moil 104 nears the point of complete separation from container 102 within trimming machine 800.

[0050] Conveyor system 706 may be any contrivance to rotate product 100. This rotation may cause product 100 to move in the direction of arrow 718 or merely to turn around longitudinal axis 112. As noted above, conveyor system 706 may include conveyor belt 708 disposed about wheel 710 and wheel 712. Conveyor belt 708 may be a continuous belt that moves about wheels 701 and 712 in the direction of arrows 718 and 720. Conveyor belt 708 may be backed by conveyor rail 714.

[0051] Conveyor rail 714 and blade rail 704 may be viewed as two parallel rails of a piece of machinery, here conveyor system 706. With cam 130 having a perimeter of constant width, product 100 may be moved between conveyor rail 714 and blade rail 704 by conveyor belt 708 over blade 702 at trim line 103. This may work to separate moil 104 from container 102.

[0052]FIG. 8 illustrates spin trimming method 800 of the invention. To start method 800, product 100 may be presented at step 802. At step 804, at least one product 100 may be placed on bottom guide 716. At step 806, bottom guide 716 may urge product 100 to move in the direction of arrow 722 so that groove 124 (FIG. 3) may engage guide rod 724 and move along a path as a function of guide rod 724. At step 808, guide rod 724 may elevate product 100 so that cam 130 and cam 122 (FIG. 3) may encounter conveyor belt 708.

[0053] At step 810, conveyor system 706 may move conveyor belt 708 so as to rotate product 100 between blade rail 704 and conveyor rail 714. This rotation may cause product 100, now removed from bottom guide 716 (FIG. 7B), to move, here rotate, in the direction of arrow 722.

[0054] At step 812, trim line 103 may encounter blade 702. As product 100 rotates in the direction of arrow 722, the distance between trim line 103 and blade 702 may vary according to the profile of cam 130. Where the profile of cam 130 is developed from Reuleaux triangle 400, the distance between trim line 103 and blade 702 may vary according to the discussion in connection with FIG. 6. This variation of distance between trim line 103 and blade 702 may cause the angular relationship between a stationary knife, here blade 702 and the surface being cut, here trim line 103, to vary such that the length over which blade 702 is used for a given trim segment along trim line 103 may be less than the maximum.

[0055] At step 814, moil 104 may be separated from container 102 so that container 102 may drop to bottom guide 716. At step 816, moil 104 may be carried off to a recycle container (not shown) and container 102 may be moved in the direction of arrow 722 as now urged by bottom guide 716.

[0056] The exemplary embodiments described herein are provided merely to illustrate the principles of the invention and should not be construed as limiting the scope of the subject matter of the terms of the claimed invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. Moreover, the principles of the invention may be applied to achieve the advantages described herein and to achieve other advantages or to satisfy other objectives, as well.

[0057] Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art. 

What is claimed is:
 1. A non-circular product, comprising: a container having a cross section that defines at least one flat side; a moil coupled to the container at a trim line, the moil having a first cam, the first cam having at least one lobe.
 2. The non-circular product of claim 1 wherein the cross section of the container is a polygon cross section.
 3. The non-circular product of claim 1 wherein the cam assumes the shape of a closed curve of constant width.
 4. The non-circular product of claim 4 wherein the closed curve defines an equilateral configuration.
 5. The non-circular product of claim 1 wherein the first cam defines a perimeter, the perimeter having a plurality of segments that are derived from the principles of the Reuleaux triangle.
 6. The non-circular product of claim 5 wherein the moil includes a second cam and wherein the first cam is disposed between the container and the second cam so as to form a groove.
 7. The non-circular product of claim 5 wherein the polygon cross section defines a triangle and the container includes a lip disposed between the trim line and the container.
 8. The non-circular product of claim 7 wherein the first cam and the lip form a trim groove having a first opening distance and wherein the first cam is part of a guide, the guide further having at least one depression formed into the guide at an angle that presents a second opening distance that is greater than the first opening distance.
 9. The non-circular product of claim 1, wherein the first cam defines a plurality of non-circular curves of constant width.
 10. The non-circular product of claim 1, wherein the polygon cross section defines a plurality of vertices that define a smooth curve.
 11. A moil, comprising: a first cam having at least one lobe.
 12. The non-circular product of claim 11 wherein the cam assumes the shape of a closed curve of constant width.
 13. The non-circular product of claim 12 wherein the closed curve defines an equilateral configuration.
 14. The moil of claim 11 wherein the first cam defines a perimeter, the perimeter having a plurality of segments that are derived from the principles of the Reuleaux triangle.
 15. The moil of claim 11 wherein the moil includes a second cam that forms a groove with the first cam.
 16. The moil of claim 11, further comprising: a lever disposed above the first cam.
 17. A method to trim a non-circular product, comprising: presenting the non-circular product, the non-circular product including a container having a polygon cross section and a moil coupled to the container at a trim line, wherein the moil includes a first cam having at least one lobe; placing the non-circular product in a trimming machine the trimming machine having a blade, a first rail, and a second rail, wherein the trim line aligns with the blade and the first cam is disposed between the first rail and the second rail; and urging the non-circular product over the blade.
 18. The method of claim 17, the trimming machine further including a bottom guide, wherein placing the non-circular product in the trimming machine includes moving the non-circular product along the bottom guide.
 19. The method of claim 17, wherein urging the non-circular product over the blade includes engaging the first cam with a conveyor belt. 